Hi.
I would like to control each color of my RGB LED using PWM and Arduino.
Some info about LED is:
Common anode RGB LED 20 Watt
Input voltage:
DC Forward Voltage (VF): Red: 10.8-13.2V, Green: 18.0-19.8V, Blue: 18.0-19.8V
DC Forward current (IF): 350mA (for each color)
So I' ve got few questions.
1)Do parts from second links are appropriate for my diode (MOSFET IRF520 and 2N3904)?
2)I've got PCA9685 chip (12 bit PWM). I wonder if using this chip with Arduino and LED will make any difference in controling this LED?
3) Why this solution - building circuit from base - is worse or better than using LED drivers from stores?
matoex:
Last few days I was trying to use PT4115 chip with varying results
but finally I want to build my own circuit.
What do you mean with that. The PT4115 is perfect for this task.
Switching constant current control is a lot better than the linear (=hot) circuits you're trying to build.
To use the three PT4115 needed for this LED, you need to separate the common anodes by cutting the connection bar.
The PT4115 has a control pin that can be connected directly to an Arduino PWM pin. Share grounds.
A PCA9685 would be a better option, because of 12-bit PWM (smoother dimming).
The LED pictured (strings of 6), with a PT4115, needs a 24volt supply.
Picture shows a homegrown PCA9685/PT4115 board that could control five of those 20watt LEDs without getting hot.
Leo..
I started new topic cause now I am using bigger light source, not LED strip but high power diode and first problem is not i2c, but supplying. But if admin have privileges, these topics can be join together.
I was trying to use PT4115 and that even somehow worked (after cutting common anode bar), but this chip is small and I had some troubles in soldering and connecting it - so I wanted to find out if I can build bigger circuit which would have simillar functions as PT4115.
On the other hand, now I see that PT4115 and PCA9685 working together are good solution.
I will try to build something to simillar to your board. Can you tell me, do u use any uC in this board? I can't see there any microcontroller.
matoex:
I will try to build something to simillar to your board. Can you tell me, do u use any uC in this board? I can't see there any microcontroller.
No MCU on this board.
The only link to the board is a two-wire I2C bus (and 5volt/ground).
So any Arduino with I2C can be used.
I currently use two of these boards, connected to a Mega with ethernet shield.
Leo..
